Method for reducing power consumption in bluetooth and CDMA modes of operation

ABSTRACT

Method for reducing power consumption in Bluetooth and CDMA modes of operation is disclosed. According to a disclosed embodiment, the time for a next scheduled CDMA wakeup process to be performed by a CDMA module is established. Thereafter, if the next CDMA wakeup process is scheduled to be performed before the next Bluetooth wakeup process, a Bluetooth wakeup process is synchronized to be performed by a Bluetooth module at the same time as the next CDMA wakeup process. Following, when the time arrives for the CDMA module to perform the next CDMA wakeup process, the Bluetooth module also performs the Bluetooth wakeup process.

FIELD

The present invention relates generally to wireless communicationdevices and systems and more specifically to reducing power consumptionin wireless communication devices.

BACKGROUND

Bluetooth is a wireless personal area network technology supportingwireless voice and data communication between different devices that aretypically within ten meters of one another. A number of differentdevices can be Bluetooth-enabled, for example, cell phones, personaldigital assistants or laptop computers. Each such device is equippedwith Bluetooth components, including a receiver and transmitter,allowing it to communicate with other similarly equipped devices nearbywithout the use of cables or other physical connections.

As an example, a wireless code division multiple access (CDMA) cellphone can be Bluetooth-enabled, meaning that the cell phone would beable to communicate in both the CDMA network and the Bluetooth network.Such a Bluetooth-enabled CDMA cell phone would comprise both Bluetoothand CDMA components.

In Bluetooth-enabled devices, for example a Bluetooth-enabled CDMA cellphone (“phone”), the Bluetooth component assumes a standby mode when thedevice is not actively communicating with other Bluetooth-enableddevices, i.e. it is not participating in a Bluetooth network. While instandby mode, the Bluetooth component searches for otherBluetooth-enabled devices by periodically performing a wakeup processduring which process it scans the surrounding environment for otherBluetooth-enabled devices. If the Bluetooth component encounters otherBluetooth-enabled devices during the scanning process and determinesthat a connection is needed, it can perform certain protocols in orderto establish a short-range, wireless connection between the phone andsuch other devices. Otherwise, the scanning task is turned off until anext wakeup process. The standby cycle of waking-up, scanning andturning off repeats typically once, twice, or four times every 1.28seconds for the duration of the standby period. However, it isappreciated that certain Bluetooth specifications may vary the timingand pattern of the cycle, for example requiring that the process beperformed continuously for 1.28 seconds, or repeating the processsixteen times every 1.28 seconds. Further, certain Bluetoothspecifications may require that the Bluetooth wakeup process berepeated, for example, at least once every 1.28 seconds, every 2.56seconds, or any other interval which a particular specification mayrequire.

While the phone's Bluetooth component scans for other Bluetooth-enableddevices as discussed above, the phone's CDMA component performs CDMArelated tasks. Since CDMA requires precise time synchronization betweenthe phone and the base station, one task the CDMA component has toperform is to synchronize with the base station. In order to synchronizewith the base station while in idle mode, the CDMA component “wakes up”periodically during its allotted time slots to receive and process pilotsignals from the base station on the CDMA Paging Channel. The CDMAcomponent can synchronize with the base station by processing the pilotsignals. For instance, the system time can be determined from theinformation embedded in the pilot signals.

How frequently the CDMA component wakes up is governed by the slot cycleindex, which can be set by either the phone or the base station, as isknown in the art. If the slot cycle index is zero, the CDMA componentperforms a wakeup process every 1.28 seconds, i.e. its allotted timeslot comes around every 1.28 seconds. Alternatively, the slot cycleindex can be set at, for example, one, in which case the wakeup processis performed every 2.56 seconds, or two, in which case the wakeupprocess is performed every 5.12 seconds. Thus, the lower the slot cycleindex, the more frequently the wakeup process is repeated and thegreater the power consumed.

Whether it is the Bluetooth component waking up and scanning for otherBluetooth-enabled devices and then shutting down, or the CDMA componentwaking up and synchronizing with the base station and then shuttingdown, power is consumed. Further, because each of the processes isperformed repeatedly, the amount of power consumed can quickly drain thephone's power supply. Wasteful or excessive power consumption is ofparticular concern in wireless devices since it can hinder the device'soperation and detract from its usefulness.

There is therefore a need in the art for a method and related system toreduce the amount of power consumed by various components of a Bluetoothenabled device, such as a Bluetooth-enabled CDMA cell phone.

SUMMARY

Embodiments disclosed herein address the above stated needs bysynchronizing the time when a Bluetooth module performs a wakeup processto the time when a CDMA module performs a wakeup process in aBluetooth-enabled device, such as a Bluetooth-enabled CDMA cell phone.

In one aspect of the invention, the time for the next scheduled CDMAwakeup process to be performed by the CDMA module is established. Oncethe time for the next scheduled CDMA wakeup process has beenestablished, the next Bluetooth wakeup process can be synchronized to beperformed by the Bluetooth module at the same time. In one aspect, thenext Bluetooth wakeup process is only synchronized with the next CDMAwakeup process if the next CDMA wakeup process is scheduled to beperformed before the next Bluetooth wakeup process is scheduled to beperformed. As an example, the times for when the next CDMA wakeupprocess and the next Bluetooth wakeup process are to be performed can beestablished from the current CDMA time and current Bluetooth time,respectively. Thereafter, when the time arrives for the CDMA module toperform the next CDMA wakeup process, the Bluetooth module also performsa Bluetooth wakeup process. In this manner, the CDMA and Bluetoothwakeup processes can be performed substantially simultaneously, leadingto a significant reduction in the power consumed by theBluetooth-enabled device from performing each wakeup process separately.

In another aspect, a wireless mobile unit for synchronizing the nextBluetooth wakeup process with the next CDMA wakeup process can beassembled comprising a CDMA module configured to perform a CDMA wakeupprocess at a next scheduled time. The wireless mobile unit can furthercomprise a processor configured to synchronize the time of the nextBluetooth wakeup process to the time of the next CDMA wakeup process.Additionally, the wireless mobile unit can comprise a Bluetooth moduleconfigured to perform a Bluetooth wakeup process substantiallysimultaneously with when the CDMA module performs the next scheduledCDMA wakeup process.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an exemplary wireless communication systemin accordance with one embodiment of the invention.

FIG. 2 shows three graphs illustrating the synchronization of wakeupschedules utilizing the system of FIG. 1.

FIG. 3. is a flowchart of a process for synchronizing the wakeupschedules of a Bluetooth module and a CDMA module in a wireless mobileunit in accordance with one embodiment of the invention.

DETAILED DESCRIPTION

The present invention is directed to a method for reducing powerconsumption in Bluetooth and CDMA modes of operation. Although theinvention is described with respect to specific embodiments, theprinciples of the invention, as defined by the claims appended herein,can obviously be applied beyond the embodiments of the descriptiondescribed specifically herein. Moreover, certain details have been leftout in order to not obscure the inventive aspects of the invention. Thespecific details not described in the present application are within theknowledge of a person of ordinary skill in the art.

The drawings in the present application and their accompanying detaileddescription are directed to merely example embodiments of the invention.To maintain brevity, other embodiments of the invention that use theprinciples of the present invention are not specifically described inthe present application and are not specifically illustrated by thepresent drawings. The word “exemplary” is used exclusively herein tomean “serving as an example, instance, or illustration.” Any embodimentdescribed herein as “exemplary” is not necessarily to be construed aspreferred or advantageous over other embodiments.

FIG. 1 illustrates an exemplary wireless communication system inaccordance with one embodiment of the invention. Exemplary wirelesscommunication system 100 shown in FIG. 1 can comprise, for example, partof a code division multiple access (“CDMA”) communication system. Thegeneral principles of CDMA communication systems, and in particular thegeneral principles for generation of spread spectrum signals fortransmission over a communication channel is described in U.S. Pat. No.4,901,307 entitled “Spread Spectrum Multiple Access Communication SystemUsing Satellite or Terrestrial Repeaters” and assigned to the assigneeof the present invention. The disclosure in that patent, i.e. U.S. Pat.No. 4,901,307, is hereby fully incorporated by reference into thepresent application. Moreover, U.S. Pat. No. 5,103,459 entitled “Systemand Method for Generating Signal Waveforms in a CDMA Cellular TelephoneSystem” and assigned to the assignee of the present invention, disclosesprinciples related to PN spreading, Walsh covering, and techniques togenerate CDMA spread spectrum communication signals. The disclosure inthat patent, i.e. U.S. Pat. No. 5,103,459, is also hereby fullyincorporated by reference into the present application. Further, thepresent invention utilizes time multiplexing of data and variousprinciples related to “high data rate” communication systems, and thepresent invention can be used in “high data rate” communication systems,such as that disclosed in U.S. patent No. 6,574,211 entitled “Method andApparatus for High Rate Packet Data Transmission” issued Jun. 3, 2003,and assigned to the assignee of the present invention. The disclosure inthat patent is also hereby fully incorporated by reference into thepresent application.

As shown in FIG. 1, the invention's exemplary wireless communicationsystem 100 comprises Bluetooth device 110, wireless mobile unit 140 andCDMA base station 180. Bluetooth device 110 can be any Bluetooth-enableddevice, for example, a laptop computer equipped with Bluetoothcomponents. Bluetooth device 110 is configured to communicate with otherBluetooth-enabled devices utilizing transmitter/receiver 112 and antenna114.

Continuing with FIG. 1, wireless mobile unit 140 of wirelesscommunication system 100 might be, for example, a Bluetooth-enabled CDMAcell phone in the present embodiment. As such, wireless mobile unit 140comprises both Bluetooth and CDMA components, i.e. Bluetooth module 142and CDMA module 144, respectively. According to the present invention,Bluetooth module 142 and CDMA module 144 share processor 146, which canbe configured to monitor and direct the wakeup/sleep cycles of Bluetoothmodule 142 in standby mode and the wakeup/idle cycles of CDMA module 144in idle mode. Further, as shown, wireless mobile unit 140 comprisesclock reference 160, which can be configured to provide Bluetooth module142 and CDMA module 144 with a common source of time.

As discussed above, when a Bluetooth-enabled device is not activelycommunicating in a Bluetooth network, the device's Bluetooth componentassumes a standby mode from which it “wakes up” periodically in order toscan for other Bluetooth-enabled devices. Further, during the wakeupprocess, the Bluetooth component determines whether it is necessary toestablish a connection with the Bluetooth-enabled devices it encounters.Scanning the surrounding environment for other Bluetooth-enabled devicesis done in a manner known in the art and may involve, for example, thetransmission, reception and processing of specific paging signals. It isnoted that the process of waking up, scanning and then shutting downperformed by Bluetooth module 142 is also referred to as a “Bluetoothwakeup process” in the present application.

Referring again to FIG. 1, Bluetooth module 142 has Bluetoothtransmitter/receiver 148 which is connected to Bluetooth antenna 150.During standby mode, Bluetooth module 142 can utilize Bluetoothtransmitter/receiver 148 and Bluetooth antenna 150 to scan theenvironment for other Bluetooth-enabled devices, e.g. Bluetooth device110. In the present embodiment, Bluetooth module 142 is configured toperform a Bluetooth wakeup process twice every 1.28 seconds. However,those skilled in the art will appreciate that Bluetooth module 142 canbe configured to perform a Bluetooth wakeup process at other intervals,for example every 1.28 seconds, every 0.32 seconds, or every 0.16seconds. Further, it is appreciated that certain Bluetoothspecifications may require that Bluetooth module 142 be configured toperform a Bluetooth wakeup process, for example, at least once every1.28 seconds, every 2.56 seconds, or any other interval required by theparticular Bluetooth specification. As shown in FIG. 1, Bluetooth device110 and Bluetooth module 142 can communicate with each other viaBluetooth airlink 116 using their respective transmitter/receiver andantenna elements.

Bluetooth module 142 further comprises clock 158. In one embodiment,clock 158 is the internal clock for Bluetooth module 142. Clock 158 canbe, for example, a 28-bit counter that tracks a current Bluetooth timeand relays the current Bluetooth time to processor 146. It is noted thatthe current Bluetooth time is also referred to as “BT_(current)” in thepresent application.

Continuing with FIG. 1, CDMA module 144 of wireless mobile unit 140comprises CDMA transmitter/receiver 152, which is connected to CDMAantenna 154. CDMA module 144 utilizes CDMA transmitter/receiver 152 andCDMA antenna 154 to communicate in a CDMA network, and more particularlywith CDMA base station 180, via CDMA airlink 184. CDMA module 144communicates with CDMA base station 180 by utilizing CDMAtransmitter/receiver 152 and CDMA antenna 154 to transmit and receivesignals. At the same time, CDMA base station 180 utilizes base stationantenna 182 to receive signals from, and transmit signals to, CDMAmodule 144. Communication between CDMA module 144 and CDMA base station180 is done in a manner known in the art.

When wireless mobile unit 140 is not actively communicating in the CDMAnetwork, CDMA module 144 assumes an idle mode. CDMA module 144 engagesin a number of tasks while it is in idle mode, including the task ofsynchronizing with CDMA system time. As is known in the art, therobustness of communication in a CDMA network depends in part on thetime-synchronization of each component in the CDMA network, includingmobile units, base stations, base station controllers, etc.

In order to synchronize with CDMA system time, CDMA module 144 utilizestransmitter/receiver 152 and CDMA antenna 154 to receive a pilot signaltransmitted by CDMA base station 180. The received pilot signal isprocessed and the current CDMA system time determined from the datacontained in the pilot signal. The processing of the pilot signal byCDMA module 144 and the determination of the current CDMA system timetherefrom are done in a manner known in the art. In the presentembodiment, the “current” time for CDMA module 144, which is alsoreferred to as CDMA_(current) in the present application, is set to theCDMA system time derived from the pilot signal. In one embodiment, clockreference 160 provides CDMA module 144 and Bluetooth module 142 with acommon source of time such that the “current” time for both modules,i.e. BT_(current) and CDMA_(current), are the same. In anotherembodiment, clock reference 160 provides CDMA module 144 and Bluetoothmodule 142 with a common clock, but the absolute values of BT_(current)and CDMA_(current) may be different. Once CDMA_(current) has beenestablished, it is relayed to processor 146. It is noted that theprocess of waking up, synchronizing with base station 180 and shuttingdown performed by CDMA module 144 is also referred to as a “CDMA wakeupprocess” in the present application.

How frequently the CDMA component wakes up is governed by the slot cycleindex (“SCI”), which can be set by either the phone or the base stationin a manner known in the art. For example, if the SCI for CDMA module iszero, then CDMA module 144 performs a CDMA wakeup process every 1.28seconds. Alternatively, the SCI can be set at, for example, one, inwhich case a CDMA wakeup process is performed every 2.56 seconds, or theSCI can be set at two, in which case the wakeup process is performedevery 5.12 seconds. It is noted that the lower the SCI, the morefrequently CDMA module 144 performs CDMA wakeup processes. In thepresent embodiment, the SCI is for CDMA module 144 is set at zero, i.e.CDMA module 144 is set to perform a CDMA wakeup process every 1.28seconds.

Continuing with FIG. 1, processor 146 uses the information it receivesfrom clock 158, i.e. BT_(current), and from CDMA module 144, i.e.CDMA_(current), in order to synchronize the wakeup schedule of Bluetoothmodule 142 with the wakeup schedule of CDMA module 144. In the presentembodiment, in order to synchronize the two wakeup schedules, processor146 has to determine how much time remains until the next wakeup processis scheduled for both Bluetooth module 142 and CDMA module 144. Therespective times of the next scheduled wakeup process are hereinafterreferred to as BT_(next) for Bluetooth module 142, and as CDMA_(next)for CDMA module 144.

Processor 146 can be configured to determine BT_(next) and CDMA_(next)based on how frequently Bluetooth wakeup processes and CDMA wakeupprocesses, respectively, are set to be performed. As stated above,Bluetooth module 142 can be set to perform a Bluetooth wakeup process atdifferent intervals or frequency, e.g. once every 0.64 seconds, and CDMAmodule 144 can be set to perform a CDMA wakeup process every 1.28seconds, every 2.56 seconds, or every 5.12 seconds, depending on itsSCI. Thus, processor 146 can determine BT_(next) by monitoring whenBluetooth module 142 last performed a Bluetooth wakeup process and thencalculating when the next Bluetooth wakeup process is to be performed.Thus, as an illustration, if processor 146 determines that Bluetoothmodule 142 last performed a Bluetooth wakeup process at time T, andBluetooth module 142 is set to perform a Bluetooth wakeup process every0.64 seconds, then processor 146 can calculate BT_(next) to be T plus0.64 seconds. Similarly, if processor 146 determines that CDMA module144 last performed a CDMA wakeup process at time Y, and CDMA module 144is set to perform a CDMA wakeup process every 1.28 seconds, i.e. its SCIis set at zero, then processor 146 can calculate CDMA_(next) to be Yplus 1.28 seconds.

Once the time for the next scheduled wakeup process has been establishedin the manner described above, the time remaining until that nextscheduled wakeup process can be determined by calculating the timedifference between the current time and the time of that next scheduledwakeup process. Accordingly, processor 146 can determine the timeremaining until the next scheduled CDMA wakeup process as CDMA_(next)less CDMA_(current). In the present application, the time remaininguntil the next scheduled CDMA wakeup process is also referred to asCDMA_(interval).

Continuing with FIG. 1, processor 146 synchronizes the wakeup scheduleof Bluetooth module 142 to the wakeup schedule of CDMA module 144 bydetermining when the next Bluetooth wakeup process is to be performed inrelation to when the next CDMA wakeup process is to be performed. Ifprocessor 146 determines that the next Bluetooth wakeup process isscheduled to be performed later than the next CDMA wakeup process,processor 146 will move the wakeup schedule of Bluetooth module 142forward such that Bluetooth module 142 performs the next Bluetoothwakeup process at the same time CDMA module 144 performs the next CDMAwakeup process. In other words, processor 146 can trigger Bluetoothmodule 142 to perform its next Bluetooth wakeup process at CDMA_(next),rather than waiting until BT_(next). The next Bluetooth wakeup processwould thus be synchronized with the next CDMA wakeup process. It isnoted that the “new” or “synchronized” time for the next Bluetoothwakeup process is also referred to as BT_(new) in the presentapplication. The task of synchronizing the wakeup schedule of Bluetoothmodule 142 with the wakeup schedule of CDMA module 144 can be performedby software or in hardware in processor 146 of wireless mobile unit 140.

Synchronizing the two wakeup schedules reduces the power consumption ofwireless mobile unit 140, because the power necessary to separately turnon Bluetooth module 142 and CDMA module 144 when they perform theirrespective wakeup processes can be shared when the two modules areturned on at the same time. Thus, FIG. 1 illustrates an exemplarywireless communication system wherein a wireless mobile unit configuredto communicate in both a Bluetooth network and a CDMA networksynchronizes the wakeup schedules of its Bluetooth module and its CDMAmodule in order to reduce the power consumption associated withunsynchronized wakeup schedules.

Referring now to FIG. 2, graphs 200, 240 and 270 illustrate the resultof synchronizing the wakeup schedule of a Bluetooth module to the wakeupschedule of a CDMA module in a wireless mobile unit such as, forexample, wireless mobile unit 140 of FIG. 1, according to oneembodiment. Thus, references will be made to wireless mobile unit 140 inorder to facilitate discussion of graphs 200, 240 and 270.

Graph 200 illustrates a time sequence of the wakeup schedule for a CDMAmodule in a wireless mobile unit, e.g. CDMA module 144 in wirelessmobile unit 140. In graph 200, axis 202 shows the on/off state of CDMAmodule 144, and axis 204 corresponds to time. The current CDMA systemtime, which can be derived from a pilot signal received from a basestation as discussed above, is shown as CDMA_(current) time 206. CDMAmodule 144 is in idle mode at CDMA_(current) time 206 and not performinga CDMA wakeup process, i.e. CDMA module 144 is “off”. However, atCDMA_(next) time 208, CDMA module 244 turns on and begins CDMA wakeupprocess 214. The time interval between CDMA_(current) time 206 andCDMA_(next) time 208 is shown in graph 200 as interval 210. Thus,interval 210 represents the time period between the current CDMA timeand the time when the next CDMA wakeup process is to be performed.Interval 212 represents the time between the start of CDMA wakeupprocess 214 and the start of CDMA wakeup process 216. Interval 212 canbe, for example, 1.28 seconds, meaning that CDMA module 144 is set toperform a CDMA wakeup process every 1.28 seconds. In other words, CDMAmodule 144's SCI is set at zero.

Referring now to graph 240 of FIG. 2, a time sequence of a wakeupschedule for the wireless mobile unit's Bluetooth module, e.g. Bluetoothmodule 142 of wireless mobile unit 140, prior to synchronization to theCDMA module's wakeup schedule, is illustrated. In graph 240, axis 242shows the on/off state of Bluetooth module 142, while axis 244corresponds to time. It is seen that at BT_(current) time 246, Bluetoothmodule 142 is “off” and not performing a Bluetooth wakeup process.However, at BT_(next) time 248, Bluetooth module 142 turns on and beginsBluetooth wakeup process 250. The time interval between BT_(current)time 246 and BT_(next) time 248 is represented by interval 252. Thus,interval 252 is the length of time between current Bluetooth time andthe time of the next scheduled Bluetooth wakeup process, i.e. Bluetoothwakeup process 250. Following an elapsed time equal to interval 254subsequent to BT_(next) time 248, Bluetooth module 142 performsBluetooth wakeup process 256, and further, following another elapsedtime equal to interval 258, Bluetooth module 142 performs Bluetoothwakeup process 260. In the present embodiment, Bluetooth module 142 canbe set to perform a Bluetooth wakeup process every 0.64 seconds. Thus,each interval 252, 254, and 258 is equal to 0.64 seconds. Those skilledin the art, however, will appreciate that Bluetooth module 142 can beset to perform Bluetooth wakeup processes at other intervals orfrequencies, for example, once every 1.28 seconds or once every 0.32seconds.

In comparing graphs 200 and 240 in FIG. 2, it is seen that interval 252is greater than interval 210. In other words, the length of time beforethe next Bluetooth wakeup process, i.e. Bluetooth wakeup process 250, isscheduled to be performed is greater than the length of time before thenext CDMA wakeup process, i.e. CDMA wakeup process 214, is scheduled tobe performed. This difference in time between when the next wakeupprocesses are scheduled to be performed can result in a significantdrain on the power supply of wireless mobile unit 140, because Bluetoothmodule 142 and CDMA module 144 have to be turned on separately toperform their wakeup processes.

Referring now to graph 270, a post-synchronization time sequence for thewakeup schedule of Bluetooth module 142 is illustrated. In graph 270,axis 272 shows the on/off state of Bluetooth module 142, and axis 274corresponds to time. Further, BT_(current) time 276 in graph 270 is thesame as BT_(current) time 246 in graph 240, meaning that the “current”Bluetooth time is the same in both graphs. However, as shown in graph270, the next scheduled Bluetooth wakeup process, i.e. Bluetooth wakeupprocess 280, has been “rescheduled” as a result of synchronization andis now set to be performed at BT_(new) time 278. Thus, rather thanhaving Bluetooth module 142 perform the next Bluetooth wakeup process atBT_(next) time 248 as shown in graph 240, the outcome of synchronizingthe wakeup schedule of Bluetooth module 142 to the wakeup schedule ofCDMA module 144 is a temporal shift of the next Bluetooth wakeupprocess, such that the next Bluetooth wakeup process is performed at thesame time as the next CDMA wakeup process. More particularly,synchronization results in the equalization of interval 282 in graph 270and interval 210 in graph 200, leading to the concurrent performance ofBluetooth wakeup process 280 and CDMA wakeup process 214, at BT_(new)time 278 and CDMA_(next) time 208, respectively. This synchronization ofBluetooth wakeup process 280 with CDMA wakeup process 214 means thatBluetooth module 142 and CDMA module 144 can be powered on at the sametime to perform their wakeup processes, resulting in a significantreduction in power consumption by wireless mobile unit 140.

Continuing with graph 270, Bluetooth wakeup process 286 followsBluetooth wakeup process 280 after a length of time equal to interval284 has elapsed, and Bluetooth wakeup process 290 follows after anotherelapsed time equal to interval 288. It is noted that Bluetooth wakeupprocesses 286 and 290 are equivalent to Bluetooth wakeup processes 256and 260 in graph 240, shifted forward as a result of the synchronizationof Bluetooth wakeup process 280 with CDMA wakeup process 214. Graphs200, 240 and 270 in FIG. 2 thus illustrate the result of synchronizingthe wakeup schedules of Bluetooth module 142 and CDMA module 144 inwireless mobile unit 140, resulting in a reduction in the amount ofpower consumed by wireless mobile unit 140.

FIG. 3 shows flowchart 300 describing an exemplary process forsynchronizing the wakeup schedules of a Bluetooth module and a CDMAmodule in a wireless mobile unit in accordance with one embodiment. Moreparticularly, the process shown in flowchart 300 can be performed by awireless mobile unit such as wireless mobile unit 140 in FIG. 1, whichcomprises both a Bluetooth component, i.e. Bluetooth module 142, and aCDMA component, i.e. CDMA module 144. Thus, for illustrative purposes,the process shown in flowchart 300 will be described in the context ofwireless mobile unit 140 in FIG. 1.

Continuing with FIG. 3, the process for synchronizing the wakeupschedules of a Bluetooth module and a CDMA module in a wireless mobileunit begins at step 310 when, for example, wireless mobile unit 140 isnot communicating in either a Bluetooth network or a CDMA network. Inother words, the process begins when Bluetooth module 142 is in standbymode, and CDMA module 144 is idle. At step 312, the current Bluetoothtime and the current CDMA time are determined. For example, currentBluetooth time, or BT_(current), can be determined by an internal clockin Bluetooth module 142, which tracks the current Bluetooth time.Current CDMA time, or CDMA_(current), can be determined, for instance,from the data in a pilot signal transmitted by a base station andreceived by CDMA module 144. In one embodiment, clock reference 160provides CDMA module 144 and Bluetooth module 142 with a common sourceof time such that the “current” time for both modules, i.e. BT_(current)and CDMA_(current) are the same. Also at step 312, BT_(current) andCDMA_(current) are relayed to a processor such as processor 146 ofwireless mobile unit 140 in FIG. 1 for further processing.

Continuing with flowchart 300 in FIG. 3, at step 314 of the process forsynchronizing the wakeup schedules of a Bluetooth module and a CDMAmodule in a wireless mobile unit, the time for the next scheduledBluetooth wakeup process and the time for the next scheduled CDMA wakeupprocess are determined. The time for the next scheduled Bluetooth wakeupprocess, or BT_(next), is determined based on the time the precedingBluetooth wakeup process was performed by Bluetooth module 142.BT_(next) is also a function of how often Bluetooth wakeup processes areto be performed, for example, once every 1.28 seconds, every 0.64seconds or every 0.32 seconds. In one embodiment, processor 146 monitorsthe time of the preceding Bluetooth wakeup process and calculatesBT_(next) by adding, for example, 1.28 seconds, 0.64 seconds or 0.32seconds to the time of the last Bluetooth wakeup process, depending onhow often Bluetooth wakeup processes are set to be performed. In asimilar fashion, CDMA_(next) can be calculated. In other words,processor 146 can monitor the time of the last CDMA wakeup process andthen add, for example, 1.28, 2.56 seconds or 5.12 seconds to the time ofthe last CDMA wakeup process, depending on the SCI set for CDMA module144, in order to calculate CDMA_(next).

Continuing with flowchart 300, it is determined at step 316 whetherBT_(current) plus the interval between CDMA_(next) and CDMA_(current) isgreater than BT_(next). If BT_(current) plus the interval betweenCDMA_(next) and CDMA_(current) is determined to be greater thanBT_(next), it indicates that the next CDMA wakeup process is scheduledto be performed by CDMA module 144 after the next Bluetooth wakeupprocess is scheduled to be performed by Bluetooth module 142. In such aninstance, the process for synchronizing the wakeup schedules of aBluetooth module and a CDMA module in a wireless mobile unit proceeds tostep 318, where the time for the next Bluetooth wakeup process, alsoreferred to as BT_(new), is set as BT_(next). The process then proceedsto step 322.

If at step 316 processor 146 determines instead that BT_(current) plusthe interval between CDMA_(next) and CDMA_(current) is not greater thanBT_(next), then the process proceeds to step 320. At step 320, the newtime for the next Bluetooth wakeup process, or BT_(new), is synchronizedwith CDMA_(next), i.e. BT_(new) is set as CDMA_(next). In other words,if processor 146 determines at step 316 that the next CDMA wakeupprocess is scheduled to be performed before the next Bluetooth wakeupprocess, processor 146 “reschedules” the next Bluetooth wakeup processto be performed simultaneously with the next CDMA wakeup process bysynchronizing BT_(new) with CDMA_(next).

The process for synchronizing the wakeup schedules of a Bluetooth moduleand a CDMA module in a wireless mobile unit then proceeds to step 322.At step 322, Bluetooth module 142 performs a Bluetooth wakeup processwhen BT_(new) is reached. It is noted that, if processor 146 haddetermined at step 316 that the time difference between CDMA_(next) andCDMA_(current) is not greater than the time difference between BT_(next)and BT_(current), such that BT_(new) is synchronized with CDMA_(next) atstep 320, CDMA module 144 would also perform a CDMA wakeup process atstep 322. In this manner, i.e. Bluetooth module 142 and CDMA module 144performing their wakeup process at the same time, the power consumptionof wireless mobile unit 140 can be significantly reduced since the twomodules can be powered up simultaneously.

Following step 322, the process for synchronizing the wakeup schedulesof a Bluetooth module and a CDMA module in a wireless mobile unitreturns to step 310. The process continues until, for example, Bluetoothmodule 142 exits standby mode or CDMA module 144 exits idle mode.

It is appreciated by those of skill in the art that the steps offlowchart 300 can be interchanged without departing from the scope ofthe present invention. Flowchart 300 in FIG. 3 thus illustrates anexemplary process for synchronizing the wakeup schedules of a Bluetoothmodule and a CDMA module in a wireless mobile unit, resulting in areduction in power consumption by the wireless mobile unit, inaccordance with one embodiment.

Those of skill in the art would understand that information and signalsmay be represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or any combination thereof.

Those of skill would further appreciate that the various illustrativelogical blocks, modules, circuits, and algorithm steps described inconnection with the embodiments disclosed herein may be implemented aselectronic hardware, computer software, or combinations of both. Toclearly illustrate this interchangeability of hardware and software,various illustrative components, blocks, modules, circuits, and stepshave been described above generally in terms of their functionality.Whether such functionality is implemented as hardware or softwaredepends upon the particular application and design constraints imposedon the overall system. Skilled artisans may implement the describedfunctionality in varying ways for each particular application, but suchimplementation decisions should not be interpreted as causing adeparture from the scope of the present invention.

The various illustrative logical blocks, modules, and circuits describedin connection with the embodiments disclosed herein may be implementedor performed with a general purpose processor, a digital signalprocessor (DSP), an application specific integrated circuit (ASIC), afield programmable gate array (FPGA) or other programmable logic device,discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described herein.A general purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

The steps of a method or algorithm described in connection with theembodiments disclosed herein may be embodied directly in hardware, in asoftware module executed by a processor, or in a combination of the two.A software module may reside in RAM memory, flash memory, ROM memory,EPROM memory, EEPROM memory, registers, hard disk, a removable disk, aCD-ROM, or any other form of storage medium known in the art. Anexemplary storage medium is coupled to the processor such that theprocessor can read information from, and write information to, thestorage medium. In the alternative, the storage medium may be integralto the processor. The processor and the storage medium may reside in anASIC. The ASIC may reside in a wireless mobile unit. In the alternative,the processor and the storage medium may reside as discrete componentsin a wireless mobile unit.

The previous description of the disclosed embodiments is provided toenable any person skilled in the art to make or use the presentinvention. Various modifications to these embodiments will be readilyapparent to those skilled in the art, and the generic principles definedherein may be applied to other embodiments without departing from thespirit or scope of the invention. Thus, the present invention is notintended to be limited to the embodiments shown herein but is to beaccorded the widest scope consistent with the principles and novelfeatures disclosed herein.

1. A method for synchronizing a wakeup schedule for a BLUETOOTH moduleand a wakeup schedule for a CDMA module in a wireless mobile unit, saidmethod comprising: determining a current CDMA time; and determining acurrent BLUETOOTH time determining a next CDMA wakeup time; determininga CDMA interval, said CDMA interval equaling said next CDMA wakeup timeminus said current CDMA time; synchronizing a new BLUETOOTH wakeup timeto said next CDMA wakeup time when said current BLUETOOTH time plus saidCDMA interval is less than said next BLUETOOTH time.
 2. A method forsynchronizing a wakeup schedule for a BLUETOOTH module and a wakeupschedule for a CDMA module in a wireless mobile unit, said methodcomprising: determining a current CDMA time and a current BLUETOOTHtime; calculating a CDMA interval, said CDMA interval equaling a nextCDMA wakeup time less said current CDMA time; and substantiallysynchronizing a new BLUETOOTH wakeup time to said next CDMA wakeup timewhen said current BLUETOOTH time plus said CDMA interval is less than anext BLUETOOTH time.
 3. The method of claim 2 further comprising:establishing said next CDMA wakeup time prior to said step ofcalculating said CDMA time interval; and establishing said nextBLUETOOTH wakeup time prior to said step of synchronizing said newBLUETOOTH time.
 4. The method of claim 2 further comprising: performinga BLUETOOTH wakeup process and a CDMA wakeup process substantially atsaid new BLUETOOTH wakeup time.
 5. The method of claim 4, wherein saidperforming comprises: powering on said BLUETOOTH module and said CDMAmodule substantially simultaneously so as to reduce said wireless mobileunit's power consumption.
 6. The method of claim 2, wherein saidwireless mobile unit comprises a BLUETOOTH-enabled CDMA cell phone.
 7. Awireless mobile unit, comprising: a CDMA module comprising a CDMAtransmitter/receiver and a CDMA antenna, said CDMA transmitter/receiverand said CDMA antenna being configured to receive a pilot signal, saidCDMA module configured to: perform a CDMA wakeup process at a next CDMAwakeup time, derive a current CDMA time from said pilot signal; aBLUETOOTH module comprising a clock configured to track a currentBLUETOOTH time, and a processor configured to: calculate a CDMA intervalequaling said next CDMA wakeup time minus said current CDMA time,substantially synchronize a new BLUETOOTH wakeup time to a next CDMAwakeup time when said current BLUETOOTH time plus said CDMA interval isless than a next BLUETOOTH time.